The present invention relates to communication systems. More particularly, the present invention relates to methods of and generators for generating preamble sequences in the communication systems.
In a wireless communication system, a mobile device may access an infrastructure station such as a base station or a relay station by detecting a preamble sequence. In general, a preamble sequence in the time domain may include a periodic shape, which may exhibit a time-domain characteristic. Moreover, the time-domain characteristic may be maintained in a frequency-domain preamble sequence of a legacy system and a new system. A mobile device may link a communication system if a receiver of the mobile device detects a related preamble sequence of the communication system. In a multi-carrier communication system such as an orthogonal frequency division modulation (OFDM) system or an OFDM-based system, a length-64 preamble sequence may be repeated four times. That is, the time-domain preamble sequence may include “P” (in the present case, 4) periodic waveforms identical to one another. Furthermore, the number of samples of the time-domain preamble sequence is an integer multiple of the number of waveforms “P” and is evenly dividable by P. Likewise, the number of tones of the frequency-domain preamble sequence is also evenly dividable by P.
Moreover, in a wireless communication system, a new system may have a wider bandwidth than a legacy system and thus may require a longer preamble sequence than the legacy system. Given a conventional OFDM or OFDM-based system, a preamble sequence of the new system may be formed by a multiple fold of the preamble sequence of the legacy system. However, in some applications, the length of a legacy preamble sequence may not be an integer multiple of P. It may therefore be desirable to have a method of generating a preamble sequence capable of supporting both the legacy system and the new system.